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comparator




blink comparator at Lowell Observatory
Clyde Tombaugh at work on the blink comparator at the Lowell Observatory, c. 1938. Credit: Lowell Observatory
A device used to look for parallax motion, proper motion, asteroids, or variable stars by quickly alternating between views of two photographic plates taken at different times; also known as a blink comparator or blink microscope. Changes in the configuration of the objects on the plates, such as the movement of a suspected planet, are detectable by their relative motion, or new objects become apparent by their alternate appearance and disappearance.

A similar instrument is the stereocomparator, which highlights objects that have changed position by their stereoscopic appearance.


Related categories

   • OBSERVATIONAL ASTRONOMY
   • TELESCOPE EQUIPMENT AND TECHNIQUES